Pneumococcal antibody concentrations and carriage of pneumococci more than 3 years after infant immunization with a pneumococcal conjugate vaccine. oleh Adebayo K Akinsola, Martin O C Ota, Godwin C Enwere, Brown J Okoko, Syed M A Zaman, Mark Saaka, Ekpedeme D Nsekpong, Aderonke A Odutola, Brian M Greenwood, Felicity T Cutts, Richard A Adegbola